US2445263A

US2445263A - Steering gear

Info

Publication number: US2445263A
Application number: US684365A
Authority: US
Inventors: Roy E Farmer
Original assignee: Ford Motor Co
Current assignee: Ford Motor Co
Priority date: 1946-07-17
Filing date: 1946-07-17
Publication date: 1948-07-13
Anticipated expiration: 1965-07-13
Also published as: GB624350A; BE474564A; CH260001A; FR949350A; ES178936A1

Description

July 13, 1948.- R. E. FARMER 2,445,263

- v STEERING GEAR Filed July 17,1946 2 Sheets-Sheet 1 R0) 5. FZRMER INVENTOR.

July 13, 1948. R E FARMR 2,445,263 I STEERING GEAR Filed July 17,1946 2 Sheets-Sheet 2 ROY E. FARMER' INVENTOR.

Patented July 13, 1948 Roy E. Farmer, Detroit, Mich, assign'orto Ford Motor Company, Dearborn; Micha, at. 00111011259 tion of Delaware 2 Application July 1'7, 1946; Ser'iafNo. 684,3'il5'.

This-application is concerned with alvehicular steering gear and more particularly with a steering gear specifically adapted to agricutural tractors and similar heavy duty apparatus in which steering is accomplished by a steering wheel which is mounted in a vertical plane through the transverse midsection of the tractor.

Heretofore tractors have been steered through this type of centrally located gear with the output from the steering gear taken oif on either or both sides of the gear box. Where the output has been taken off only on one side, the remainder of the steering mechanism has closely followed automotive practice and made use of the conventional tie rod for connecting the two front wheels. Where the output has been taken off from both sides of the gear box through two individual steering arms, a separate drag link has been provided for each front wheel. It is this latter type of double take off steering gear with which this application is concerned.

In this double take off type of steering gear it has been heretofore deemed necessary, in order to maintain proper steering symmetry, to have the two take off shafts leading from the gear box coaxial. The use of a solid shaft extending through the gear box is precluded since the rotation of the left take off shaft is of necessity opposite in direction to that of the right hand take off shaft. In practice these requirements that the two take off shafts be coaxial and revolve in opposite directions, have led to some rather bulky, complicated and expensive structures. Applicant has discovered that proper steering geometry can be maintaianed even though the two take off shafts do not present coincident axes, and has invented a simple, rugged and inexpensive steering gear in which this discovery can be utilized. Applicants preferred structure is composed largely of parts long standard in automotive steering apparatus.

Accordingly it is an object of this invention to provide a vehicular steering gear having two take offs whose axes are non-coincident.

It is a further object of this invention to provide a tractor steering gear having two eccentric take offs and which utilizes to a large degree parts standard in automotive practice.

With these and other objects in view, the invention consists in the arrangement, construction and combination of the various parts of the improved structure as described in the specification, claimed in the claim and illustrated in the accompanying drawings, in which:

2-. "Figure l is an elevation. partially-in section. Figure 2 is a plan view-of the steering-gear-partially in section.

In Figure 1 the steering gear case is indicated generally as I0. Steering column II is mounted upon gear case I!) and encloses steering shaft I2. Steering shaft I2 terminates at its upper end in threads which accommodate nut I3 by which a steering wheel is secured to the shaft. Hour glass worm gear I4 is rigidly secured to the lower end of steering column shaft I2. This h'our glass worm gear is supported in anti-friction bearings I5. The periphery of hour glass worm gear I4 engages rotary follower It. This rotary follower is journaled on shaft I'I through needle bearing I8. The ends of shaft I! are trunnioned in supports mounted on offtake shaft I9. There are, of course, two ofi take shafts I9 in applicant's steering gear. In Figure 1 only that off take shaft to the right of steering shaft I2 is shown, Attention is directed to Figure 2 for a clear teaching of the relationship of rotary follower I6 and. off take shaft I9. Steering arms 20 which terminate in eyes 2| are splined to the outer ends of oiftake shafts I9. These offtake shafts are supported intermediate their ends in bushings 24 mounted in bosses 23 (Figure 2). This structure is shown in the sectioned portion of Figure 1 to the left of the axis of steering shaft l2. A similar mechanism is provided directly opposite that shown and operates the right hand ofitake shaft l9.

Any rotation of the steering wheel causes a correspondin rotation of hour glass worm gear I 4. This turnin of hour glass Worm gear I 4 causes rotary follower I6 to rotate about the axis of shaft I! on needle bearings I8 and also to revolve about the axis of offtake shaft I9 since sh'aft I1 is trunnioned on the end of offtake shaft I9. This rotation about the axis of ofitake shaft I9 is transmitted to the drag links (not shown) through steering arms 20 and eyes 2|.

In Figure 2, a partial section has been taken normal to the steering column and on a plane passing throu h the axes of both oiftake shafts I9. This figure shows the intermeshing of hour glass worm gear I4 and rotary follower l6. This figure also illustrates adjusting screw 25. By means of this adjusting screw, shaft I9 is movable axially to compensate for wear of the rotary follower I6 and hour glass worm gear I4. This adjusting screw 25 is secured against accidental rotation by star washer 26.

The steering gear shown is illustrated in the of the steering; gear 3 straight ahead or neutral position. In this position the axes of the two shafts l1 upon which are mounted rotary followers l6 and the axis of steering shaft I2 are parallel and approximately coplanar. The axes of offtake shafts I9 are parallel but of course are not coincident. In the form illustrated these ofitake shafts I9 are displaced from each other both vertically and horizontally, although applicant's invention contemahead of and one of which is located behind the steering column shaft and whose .axes are parallel and fall in a common plane normal to the steering column shaft, a pair of rotary followers rigidly mounted upon said ofltake shafts and operatively connecting the worm gear and offtake shafts, the axes of said rotary followers falling outside that plane normal to the offtake shafts and bisecting the hour glass worm a small but significant distance and adjusting means to move each of said rotary followers parallel to the axes of the ofitake shafts, said adjusting means being located on opposite sides of the gear case.

ROY E. FARMER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Name Date Wright Aug. 6, 1929 Marles Oct. 18, 1932 Murden Mar. 30, 1937 Merce Dec. 26, 1944 Number